As of December 28th, 2009 these are the countries that we can't do business with due to embargo restrictions.
Reference: http://www.ustreas.gov/offices/enforcement/ofac/programs/
Sudan
http://www.ustreas.gov/offices/enforcement/ofac/programs/ascii/sudan.txt
PENALTIES: Criminal fines for violating the Regulations range, upon conviction, up to $1,000,000; individuals may also face imprisonment of up to 20 years. In addition, civil penalties of up to $250,000 or twice the amount of the underlying transaction may be imposed administratively for each violation.
Syria
http://www.ustreas.gov/offices/enforcement/ofac/programs/syria/syria.shtml
PENALTIES: Criminal penalties for violating the sanctions range up to 10 years in prison, $500,000 in corporate fines and $250,000 in individual fines. In addition, civil penalties of up to $11,000 per violation may be imposed administratively.
Cuba
http://www.ustreas.gov/offices/enforcement/ofac/programs/ascii/cuba.txt
PENALTIES: Criminal penalties for violating the sanctions range up to 10 years in prison, $1,000,000 in corporate fines, and $250,000 in individual fines. Civil penalties up to $55,000 per violation may also be imposed.
North Korea
http://www.ustreas.gov/offices/enforcement/ofac/programs/ascii/nkorea.txt
PENALTIES: Criminal fines for violating the E.O. range, upon conviction, up to $1,000,000; individuals may also face imprisonment up to 20 years. In addition, civil penalties of up to $250,000 or twice the amount of the underlying transaction may be imposed administratively for each violation.
Iran (aka Persia)
http://www.ustreas.gov/offices/enforcement/ofac/programs/ascii/iran.txt
PENALTIES: Criminal penalties for violations of the Iranian Transactions Regulations may result in a fine up to $1,000,000, and natural persons may be imprisoned for up to 20 years. Civil penalties, which are not to exceed the greater of $250,000 or an amount that is twice the amount of the transaction that is the basis of the violation with respect to which the penalty is imposed may also be imposed administratively.